Reflection coefficient
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The reflection coefficient is used in physics and electrical engineering when wave propagation in a medium containing discontinuities is considered. A reflection coefficient describes either the amplitude or the intensity of a reflected wave relative to an incident wave. The reflection coefficient is closely related to the transmission coefficient.
Different specialties have different applications for the term.
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[edit] Telecommunications
In telecommunications, the reflection coefficient is the ratio of the amplitude of the reflected wave to the amplitude of the incident wave. In particular, at a discontinuity in a transmission line, it is the complex ratio of the electric field strength of the reflected wave to that of the incident wave. This is typically represented with a Γ (capital gamma).
The reflection coefficient may also be established using other field or circuit quantities.
The reflection coefficient is given by the equations below, where Z1 is the impedance toward the source, Z2 is the impedance toward the load:
The absolute magnitude of the reflection coefficient (designated by vertical bars) can be calculated from the standing wave ratio, SWR:
The reflection coefficient is displayed graphically using a Smith chart.
Source: from Federal Standard 1037C in support of MIL-STD-188
[edit] Seismology
[edit] Optics
In optics, both intensity and amplitude reflection coefficients are used. Typically, the former are represented by a capital R, while the latter are represented by a lower-case r.
[edit] References
Books
- Bogatin, Eric (2004). Signal Integrity - Simplified. Upper Saddle River, New Jersey: Pearson Education, Inc.. ISBN 0-13-066946-6. Figure 8-2 and Eqn. 8-1 Pg. 279
